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Report: Tree canopy declining in Seattle’s parks and forests

By Larry Lange
Seattle, WA (March 27, 2011)- Seattle is losing trees in its parks and urban forests, the last places you might think that would happen.

The trend, picked up by a recent study of the city’s tree canopy, results from an aging public forest that’s dying, being slowly choked by invasive plants or killed by disease. The finding about parks deviates from the study conclusion that, city-wide, Seattle’s tree canopy- the percentage of in-city ground covered by trees and their leafy branches- had grown slightly over five years.
Statistics showing the decline in the parks and natural areas appear in a report summarizing results of a 2009 study that analyzed the amount of tree cover above Seattle’s landscape. The report said the canopy in developed parks and boulevards declined from 25.3 per cent in 2002 to 24.6 percent in 2007. Tree cover at city-owned natural areas like greenbelts declined from 82.7 percent in 2002 to 80.8 percent in 2007. The study said that meant there were 60 fewer acres of parks and natural that were shaded or protected by trees in 2007. That’s a reduction equal to an area three times the size of the Safeco Field site.
The estimate was contained in a 2009 study done for the city Parks & Recreation Department by a Colorado consultant, using satellite imaging and geographic information system data. The report estimated that, overall, the tree canopy city-wide grew from 22.5 percent of its land area in 2002 to 22.9 percent by 2007. Earlier estimates said the canopy had declined from 40 percent in 1972 to as low as 18 percent in 2006 but had increased since then. There was more tree cover above private properties and along streets, though there were fewer in areas were new developments were built.
The city has a stated goal of increasing its stock of trees. The decline in park trees, largely unnoticed until now, might surprise some. City Councilwoman Sally Bagshaw, a self-described tree advocate who chairs the council’s Parks & Seattle Center Committee, said “it was news to me.” It wasn’t to Mark Mead, forester for Seattle’s Parks and Recreation department. Many of the trees in city parks and forested areas are old and have begun dying out naturally, Mead said. Occasionally, adjacent landowners will cut down a tree that’s blocking their view. At the same time, he said, tightening city budgets have meant city staffers have been unable to spend as much time pruning and watering trees that need it. Parts of the city-owned forests were established as long ago as 100 years “and those trees are reaching the age where they die and fall apart,” Mead said.
Mead estimated that there are between 100,000 and 120,000 trees in parks, green belts and other forested areas the city owns, though nobody has taken an exact count. Mead, an arborist, said trees need attention such as watering or pruning at least once every five years to keep them thriving but his crews have been averaging “somewhere between 18 and 20 years” on individual trees. Recent budget cuts have taken out one three-member tree management crew and cut two members of another crew that managed natural areas. Parts of the city-owned acreage has been logged over the years and, without replanting of larger trees, some of the land has been taken over by non-native plants like English ivy and laurel, which can choke native trees or keep new indigenous conifers from taking hold. Native Madronas have died after being isolated as other trees were lost, becoming more susceptible to fungus-borne diseases.
Mead said the city began sensing in the mid-1990s that it was losing park trees and the phenomenon isn’t obvious to everyone who doesn’t watch very closely. He said it’s been tougher to compete for the tightening supply of city cash to keep tree crews going. In budget crunches, “unfortunately, parks is the department that takes it on the chin year after year,” Bagshaw said. The city has turned to volunteers for help. Mead said the city discovered that some private citizens were caring for city-owned trees on their own. Five years ago the city and the Cascade Land Conservancy started a forest-preservation program, the Green Seattle Partnership, which uses volunteers to help restore and maintain parts of the city-owned forests.
About 500 acres are being restored, with more added as time allows. Mead said 95 to 97 percent of new trees planted in the past four years are surviving so far. Of the 6,200 acres held by the parks agency, about half of it is in forested areas such as the East and West Duwamish Greenbelts, Mead said, in addition to stands of trees in developed parks. He said the volunteer hours given so far aren’t enough to bring the forests back to sustainable levels. Each four hours of volunteer time “requires a minimum of one hour of paid staff support” as well as city cash.
“A common misconception is that once invasive plants are removed and a tree is planted that the site is restored,” he said, but “to be truly sustainable a long-term commitment is necessary….We need more folks. We need more volunteers. We need more money. It’s going to take a little while to stop the slide backwards.” He said he department needs about $3 million annually to keep its crews tending to trees and clearing unwanted brush, but the city’s recent tax-revenue crunch has drastically reduced the amount. Budget reductions for this year cut two crew members and Mead and his department is searching for ways to keep up.
Bagshaw said the city will likely have to initiate more “public-private partnerships” using neighborhors and other volunteers to take care of city trees, in the same way volunteer work cleans up neighborhoods. Can the city keep the park acreage it has and still maintain it? It’s politically tough to get rid of it. “I think it’s a fair question, but everybody loves their parks,” Bagshaw said. “At budget hearings we have, literally,1,000 people show up…and say, ‘please save our park…please plant more flowers, please plant more green space’….Really, parks are a measure of our quality of life.”Related Resources:Seattle Post-Intelligencer- Report: Tree canopy declining in Seattle’s parks and forestsGreen Seattle Partnership